While the invention covers a wide range of applications relating to the fixing and aligning of a patient's head and eye, it is particularly directed to restraining a patient's eye without interfering with the ophthalmic surgery on the exterior surface of the cornea.
When either eye of a patient is undergoing ophthalmic surgery, such as laser refractive keratoplasty (LRK), there is a requirement to control the position and orientation of both the head and eye of the patient. Precise location of a patient's head is particularly critical for LRK where the exterior surface of the cornea of the eye is recontoured or localized defects in the corneal surface are removed or reduced in severity by controlled application of pulsed laser radiation in order to improve the patient's visual capability. The position control can also be of importance during radial keratotomy (RK), linear corneal keratectomy (LCK) or other forms of corneal surgery.
Several different techniques and related apparatus for accomplishing some of these types of surgical procedures are described in publications entitled "Photoablative reprofiling of the cornea using an excimer laser: Photorefractive keratoplasty", by Marshall et al., Lasers in Ophthalmology, Vol. 1, No. 1, pp. 21-48 (1986); "Corneal sculpting using an excimer laser delivery system", by Martin et al., Proc. SPIE, Vol. 908 (1988); "Beam delivery system for UV laser ablation of the cornea", by Yoder et al., Proc. SPIE, Vol. 908 (1988). Also, techniques and apparatus are set forth in U.S. Pat. Nos. 4,665,913; 4,669,466 and 4,718,418 by L'Esperance. Experimental use of ultraviolet lasers in RK has been described by Trokel et al. in an article entitled "Excimer Laser Surgery of the Cornea", American Journal of Ophthalmology, Vol. 96, pp. 710-715 (1983). LCK has been described by Seiler et al. in an article entitled "Excimer Laser Keratectomy for Correction of Astigmatism", American Journal of Ophthalmology, Vol. 105, pp. 117-124 (1908).
The techniques and apparatus described in the cited references rely on irradiation of the cornea with pulsed laser radiation so that the irradiated tissue ablates with minimal related damage or scarring of adjacent tissue. Implicit in the application of laser radiation of any wavelength to an eye for corrective surgery is the requirement to align the eye and the laser beam accurately so that the ablative effect occurs at the proper location on the corneal surface. Retention of the initially selected alignment throughout the surgical procedure is also a required condition for success.
Prior art devices used to fixate or restrain the head during ophthalmic surgery include a variety of mechanical clamping devices and/or adjustable straps pressing against the patient's forehead, chin, temples and/or cheeks. These devices are generally structurally attached to the hospital gurney, surgical chair or equivalent supporting the patient. However, in some cases the devices are attached to the apparatus used to accomplish the surgical procedure.
Devices previously used to fixate or restrain the eye against voluntary or involuntary motions during surgery include mechanical fixtures with probes penetrating into the scleral tissue, fixtures sutured to the scleral tissue outside the visually-used (corneal) area and vacuum-operated rings contoured to interface with the eye in the general region of the scleracornea juncture (commonly known as the "limbus"). Devices of the latter type have been mentioned in the following articles: Advanced Techniques in Ophthalmic Microsurgery, Volume two: Corneal Surgery, by L. J. Girard, C. V. Mosley Company, St. Louis, pp. 156-158 (1981); "Corneal Resurfacing Apparatus and Method", by B. J. Curtin, U.S. Pat. No. 4,173,980, issued Nov. 13, 1979; and "Keratomileusis for Myopia and Aphakia", by J. I. Barraquer, Ophthalmology, Vol. 88, p. 701 (1981). Also, similar appliances are described in U.S. Pat. Nos. 4,665,913 and 4,718,418, set forth hereinbefore.
It is a problem underlying the present invention to restrain a patient's head and eye during ophthalmic surgery without interfering with the ability to carry out surgical procedures on the cornea.
It is an advantage of the present invention to provide an eye restraining device and a technique of using same which obviates the limitations and disadvantages of the prior art.
It is still another advantage of the present invention to provide an eye restraining device and a technique for using same to fixate the patient's head and either eye during surgery on an eye.
It is yet another advantage of the present invention to provide an eye restraining device and technique of using same which facilitates positional and angular alignment of the head and eye of a patient with respect to the particular instrument used in performing the surgical procedure.
It is still another specific advantage of the present invention to provide an improved eye restraining device and technique for using same for use in conjunction with surgical techniques and apparatus to reduce excessive myopia, hyperopia and/or astigmatism conditions of the patient's eye.
It is a still further advantage of the present invention to provide an improved eye restraining device and technique for using same to facilitate improvement of the patient's vision through application of LRK surgical procedures involving volumetric removal of corneal tissue with penetration into the stroma to recontour the anterior surface of the cornea or to treat ulcers or other disorders of the cornea.
It is yet a further advantage of the present invention to provide an improved eye restraining device and technique for using same whereby the fixation of the eye does not interfere with optical sighting across the vertex of the cornea and allows water or other fluids administered to the cornea in connection with surgery to drain away from said cornea.
It is another advantage of the present invention to provide an improved eye restraining device and technique for using same which permits surgical removal of the epithelium from the central region of the cornea while the eye is fixated in position and angular orientation.
The invention achieves these objects with apparatus that allows the operator to effectively position and align the eye relative to a laser beam used for LRK procedures although said invention is in no way limited to said procedures, but can be used in many applications wherein a patient's eye is to be fixed in space and oriented for diagnostic or surgical purposes.
Accordingly, there has been provided an eye restraining device including a ring-shaped element which contacts the sclera of an eye so that the cornea projects above the ring-shaped element. A second embodiment includes a head restraint including a plurality of adjustable engaging components for accommodating different sized heads.